Abstract:AIM: To investigate the role and mechanism of N6-methyladenosine(m6A)methyltransferase 3(METTL3)in the pathogenesis of diabetic cataract.
METHODS: We cultured SRA01/04 cells in low and high sugar media for 24h and measured changes in epithelial-mesenchymal transition(EMT)indicators(E-Cadherin, N-Cadherin, ZO-1 and α-SMA)using RT-qPCR and Western blot assays. Cell migration was also assessed using transwell and scratch assays. To investigate the expression level and localization of METTL3 in human lens anterior capsules tissues. Additionally, we used m6A dot blot assay to detect the m6A methylation level of cells cultured in low and high glucose media for 24h, and employed RT-qPCR and Western blot experiments to detect RNA and protein expression of METTL3 in cells. We then treated the cells with METTL3 inhibitor and measured changes in EMT markers by RT-qPCR and Western blot; m6A methylation level was detected by m6A dot blot test; cell migration was detected by Transwell. Finally, the expression of transforming growth factor-β(TGFβ1)in cultured cells was assessed by immunofluorescence staining and the expression levels of TGFβ1 and SNAIL in cells were determined using RT-qPCR and Western blot.
RESULTS: Under high glucose conditions, the expression of EMT markers, METTL3, and m6A methylation levels were significantly increased in cells(P<0.05). Furthermore, the migratory ability of cells was higher in high-sugar medium than in low-sugar medium. In human lens anterior capsules, METTL3 expression was higher in patients with diabetic cataract compared to those with age-related cataract. Importantly, treatment with the METTL3 inhibitor STM2457 inhibited EMT in cells, the expression of TGFβ1 and SNAIL, as well as m6A methylation levels in cells(all P<0.05)compared to high-sugar + dimethyl sulfoxide(DMSO)group. Moreover, the migratory capacity of cells was reduced after the addition of STM2457 compared to the high-sugar + DMSO group.
CONCLUSION:METTL3 promotes the EMT in human lens epithelial cells under high glucose conditions by activating the TGFβ1/SNAIL pathway, thus contributing to the development of diabetic cataracts.
